Deciduous trees can be messy in fall, but evergreens can be a mess year-round

By Tony Tomeo

Silicon Valley Community Newspapers

Posted:
10/30/2013 06:02:56 PM PDT

Updated:
10/30/2013 06:02:57 PM PDT

The problem with all the colorful foliage that adorns so many of the deciduous trees in autumn is that it does not stay in the trees very long. Combined with all the other less colorful deciduous foliage, as well as whatever evergreen foliage happens to fall this time of year, it will become quite a mess by winter. Rainy and windy winter weather will only make it messier by bringing down even more foliage.

Contrary to popular belief, many evergreen trees are just as messy as deciduous trees. Instead of dropping all their foliage in autumn or winter, most evergreens drop smaller volumes of foliage throughout the year. The mess is less obvious since it sneaks up slowly, but can accumulate over a few months. Only a few evergreen trees drop much of their foliage in more obvious seasonal phases.

Debris from evergreen trees is actually more likely to be a problem for plants below. Pines, cypresses, firs, spruces, cedars, eucalypti and many other evergreen trees produce natural herbicides that inhibit the emergence of seedlings of plants that would compete with them in the wild. In landscape situations, this unfortunately interferes with lawns, groundcovers and annuals. Besides walnuts and deciduous oaks, not many deciduous trees use this tactic.

Regardless, any foliar debris can be a problem if allowed to accumulate too long. Large leaves, like those of sycamore, can accumulate and shade lawn, groundcover and some dense shrubbery, and can eventually cause mildew and rot. Finely textured foliage, like that of jacaranda or silk tree, can sift through most groundcovers to the soil below, but can still make a mess on lawn.

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Before rainy weather, debris should be cleaned from gutters and downspouts. Because some foliage continues to fall through winter, gutters will likely need to be cleaned again later. Flat roofs and awkward spots that collect debris, such as behind chimneys, should also be cleaned.

Gutters at the street are more visible and accessible, so do not often accumulate enough debris to be a problem, but may need to be cleaned if they become clogged with debris washed in by the earliest rains. Fallen leaves should be raked from pavement so that it does not get dangerously slippery, or stain concrete too much.

Tree of the Week: Valley Oak

From the north end of the Sacramento Valley to the San Fernando Valley, the valley oak, Quercus lobata, is among the most familiar and distinctive of native oaks. It is the largest oak of North America, reaching more than 100 feet tall with trunks as wide as 10 feet, which is why it is rare in urban gardens. The 150-foot "Henley Oak" of Covelo is the tallest hardwood tree in North America. The oldest trees are about six centuries old.

The 2- or 3-inch-long leaves have deep and round lobes. The foliage turns only dingy yellow and then brown in autumn, and can be messy as it continues to fall through early winter, particularly since the trees have such big canopies. The gnarly limbs are strikingly sculptural while bare through the rest of winter. The gray bark is evenly furrowed.

Incidentally, Oakland, Thousand Oaks, Paso Robles and various other communities within their range are named for valley oaks. ("Roble" is the Spanish name.)